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AbstractObjectivesMethodsResultsConclusionsOne of the most frequently applied paradigms in the clinical and experimental fields for assessing working memory is the simple span task, composed of forward and backward recall conditions. However, the utility of the simple span measures and their relation to working memory modalities has yet to be elucidated. The current study aimed to address which of the span measures is more sensitive to the differentiation between forward and backward recall in the tactile, verbal, and visuo-spatial modalities, and to test if working memory modalities differ in the disparity between the two conditions.134 healthy young adults performed the Tactual, Digit, and Visuo-spatial Span tasks, producing Total Correct scores and Longest Sequence score measures.There was an interaction effect for condition and modality type, showing better performance for the forward compared to the backward recall in both measures. However, the effect size of the Longest Sequence score was significantly higher than the Total Correct score in all tasks. Furthermore, the Visuo-spatial Span exhibited a larger difference between forward and backward recall compared to the Digit and Tactual Span, whereas no difference was found between the latter two.Forward and backward recall are distinguished in all three modalities, and the Longest Sequence score is more sensitive to differentiate between storage and manipulation components of working memory than the Total Correct score. Additionally, the cognitive demand imposed by manipulation compared to storage is the greatest in the visuo-spatial modality. [ABSTRACT FROM AUTHOR]

Hearing involves more than just the central auditory pathway's operation and hearing threshold. Instead, the term 'hearing' encompasses a range of skills such as listening, comprehending, and communicating. As a result, a thorough assessment of the patient's listening effort and working memory is critical. Forty-four subjects with cochlear implantation were included in the study, 22 patients as a study group and 22 subjects as a control group. They were assessed by digit span test for working memory, speech in noise test at different SNR levels, Fatigue assessment scale and Effort assessment scale. There was a statistically significant difference in the Spin test between the study and control group. The study group showed a significant higher Spin scores at all SNR levels. There was a significant difference in both digit span forward and digit span backward tests between both the study and control group with a significant negative correlation between digit span and listening effort and fatigue scales. There was a significant statistical difference in the mean results of both the listening fatigue assessment scale and listening effort assessment scale between the study and control group where the study group showed a significant higher result in both scales. Assessing the effort associated with recognising speech is very valuable. Scales for measuring listening effort and listening fatigue as well as working memory can be easily incorporated into the basic audiological evaluation providing valuable insights for further rehabilitation. [ABSTRACT FROM AUTHOR]

Objective: The addition of Sequencing to WAIS-IV Digit Span (DS) brought about new Reliable Digit Span (RDS) indices and an Age-Corrected Scaled Score that includes Sequencing trials. Reports have indicated that these new performance validity tests (PVTs) are superior to the traditional RDS; however, comparisons in the context of known neurocognitive impairment are sparse. This study compared DS-derived PVT classification accuracies in a design that included adults with verified TBI. Methods: Participants included 64 adults with moderate-to-severe TBI (TBI), 51 healthy adults coached to simulate TBI (SIM), and 78 healthy comparisons (HC). Participants completed the WAIS-IV DS subtest in the context of a larger test battery. Results: Kruskal–Wallis tests indicated that all DS indices differed significantly across groups. Post hoc contrasts revealed that only RDS Forward and the traditional RDS differed significantly between SIM and TBI. ROC analyses indicated that RDS variables were comparable predictors of SIM vs. HC; however, the traditional RDS showed the highest sensitivity when approximating 90% specificity for SIM vs. TBI. A greater percentage of TBI scored RDS Sequencing < 1 compared to SIM and HC. Conclusion: In the context of moderate-to-severe TBI, the DS-derived PVTs showed comparable discriminability. However, the Greiffenstein et al. traditional RDS demonstrated the best classification accuracy with respect to specificity/sensitivity balance. This relative superiority may reflect that individuals with verified TBI are more likely to perseverate on prior instructions during DS Sequencing. Findings highlight the importance of including individuals with verified TBI when evaluating and developing PVTs. [ABSTRACT FROM AUTHOR]

The Reliable Digit Span (RDS) is a performance validity test (PVT) used widely within non-clinical samples, but its utility is in question in clinical groups with cognitive impairment. To investigate, RDS scores were calculated and correlated with the Neurological Predictor Scale, an informant-reported Activities of Daily Living score, and a proxy measure of intelligence (Vocabulary) for 83 adult survivors of childhood brain tumors and 105 healthy controls. Analyses were covaried for age at examination. Participants were divided into passing and failing groups at each RDS cutoff, and ANCOVAs for each of the three variables of interest covaried for age at the examination were run. RDS was correlated with all three variables of interest in survivors but only Vocabulary in controls. At the ≤7 cutoff, passing and failing survivors demonstrated significant differences across all variables of interest, while passing and failing controls differed only on Vocabulary. Differences were also found between passing and failing survivors at lower cutoffs. RDS is related to and likely impacted by various neurological and cognitive challenges faced by brain tumor survivors. Using the standard RDS cutoff of ≤7 may result in inaccurate interpretation of valid performance in this population; therefore, the use of other PVTs is recommended. [ABSTRACT FROM AUTHOR]

Lack of test norms is a major limitation in neuropsychological assessment in many non-English-speaking countries. Our objective was to generate sex-, age-, and education-adjusted, regression-based norms for three pen-and-paper-based executive function/working memory tests, viz. Victoria Stroop Test (VST), Digit Span, and Verbal Fluency, for Sinhala-Speaking Sri Lankan adults. Six-hundred and six healthy, community-living, Sinhala-speaking adults (273 men) aged 19–83 years completed VST, Digit Span (forward and backward), and Phonemic (Sinhala phonemes "N," "P," and "S") and Category (animals and vegetables) Fluency tests. We conducted multiple linear regression analyses with sex, age, and years of education fitted as predictors to model the test outcome variables. Younger age was associated with better performance in all tests except in Phonemic Fluency. Longer education was associated with better performance in all outcomes except VST errors and interference. Women had a significant but small advantage over men in VST Neutral and Color Word tests, and Phonemic Fluency. We report regression equations to predict norms for the test performance measures based on sex, age, and years of education; and the test variances accounted by these factors. We propose demographically adjusted norms for VST, Digit Span, and Verbal Fluency for Sinhala-speaking Sri Lankans aged 19–83 years, and supplement the regression formulae with a calculator that produces predicted and standard scores. These norms would help in interpreting the results of clinical samples in the future, taking into account the variability introduced by sex, age, and education. [ABSTRACT FROM AUTHOR]

Objective: Embedded validity measures are useful in neuropsychological evaluations but should be updated with new test versions and validated across various samples. This study evaluated Wechsler Adult Intelligence Scale, 4th edition (WAIS-IV) Digit Span validity indicators in post-deployment veterans. Method: Neurologically-intact veterans completed structured diagnostic interviews, the WAIS-IV, the Medical Symptom Validity Test (MSVT), and the b Test as part of a larger study. The Noncredible group included individuals who failed either the MSVT or the b Test. Of the total sample (N = 275), 21.09% failed the MSVT and/or b Test. Diagnostic accuracy was calculated predicting group status across cutoff scores on two Digit Span variables, four Reliable Digit Span (RDS) variables, and two Vocabulary minus Digit Span variables. Results: Digit Span age-corrected scaled score (ACSS) had the highest AUC (.648) of all measures assessed; however, sensitivity at the best cutoff of <7 was only 0.17. Of RDS measures, the Working Memory RDS resulted in the highest AUC (.629), but Enhanced RDS and Alternate RDS produced the highest sensitivities (0.22). Overall, cutoff scores were consistent with other studies, but sensitivities were lower. Vocabulary minus Digit Span measures were not significant. Conclusions: Digit Span ACSS was the strongest predictor of noncredible performance, and outperformed traditional RDS variants. Sensitivity across all validity indicators was low in this research sample, though cutoff scores were congruent with previous research. Although embedded Digit Span validity indicators may be useful, they are not sufficient to replace standalone performance validity tests. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to compare cognitive skills in epilepsy patients and psychogenic non-epileptic seizures (PNES) patients who have no history of frequent seizures to those of a healthy control group. Methods: This prospective cross-sectional study was conducted between January 2017 and June 2019 and included 103 epilepsy patients, 100 PNES patients, and 101 healthy controls, aged 18 to 60 years. Patients with fewer than 12 annual seizure episodes and no history of seizures during the last 30 days were added to the study. A sociodemographic data form, the Beck Anxiety and Depression Scales, Montreal Cognitive Assessment, Digit Span test, and Stroop Color-Word Interference Test were used. Results: Compared to the control group, sub-component scores were significantly lower in naming, attention, abstract thinking, and delayed recall for the epilepsy and PNES groups. Sub-component scores in orientation, executive functioning, and delayed recall were significantly lower in the epilepsy group compared to the PNES group. Digits Backward subtest scores and total Digit Span test scores were significantly lower in the epilepsy and PNES groups. Patients in the epilepsy and PNES groups took longer to complete the Stroop test and made more errors and corrections compared to the healthy controls. There was a negative correlation between the duration of the disease and the total Digit Span score in the epilepsy group. Conclusion: These findings suggest that the epilepsy group showed reduced cognitive scores even though they did not suffer from frequent seizures and were not drug-resistant. [ABSTRACT FROM AUTHOR]

Objective: The Digit Span (DS) subtest from the Wechsler Adult Intelligence Scale-4th Edition (WAIS-IV) was updated to better measure working memory which is potentially clinically relevant as prior unreplicated studies showed that sequencing tasks differentiated normal from neurologic groups. This study examines performance on DS for individuals from a memory disorder clinic diagnosed with amnestic mild cognitive impairment (aMCI), probable dementia of the Alzheimer type (DAT), or those with subjective cognitive complaints (SCC). Method: Seven hundred and six individuals were drawn from 1256 consecutive referrals who underwent a standard neuropsychological evaluation and obtained a consensus diagnosis from a neuropsychologist and a neurologist of DAT, aMCI, or having SCC. This resulted in a sample of 290 individuals with DAT, 255 with aMCI, and 161 with SCC. Results: Those with DAT performed significantly worse for DS Forward, Backward, and Total Score versus those with aMCI and SCC, whose performances were similar. Digit Span Sequencing was significantly different in each group (DAT < aMCI < SCC), with a high rate of the DAT group showing cross-task perseveration. Conclusions: The DS sequencing results differed between the three clinical groups, which is consistent with the hypothesis that working memory declines would be evident on this measure. Discontinuation of DSS due to cross-task perseveration was frequently seen in, although not unique to, the DAT group. Both poorer DSS performance and the presence of perseveration can offer useful clinical information on the context of a thorough evaluation of the aMCI/DAT spectrum. [ABSTRACT FROM AUTHOR]

The aims of the study were to investigate healthy subjects' performance on a clinical test of high-level language (HLL) and how it is related to demographic characteristics and verbal working memory (VWM). One hundred healthy subjects (20–79 years old) were assessed with the Swedish BeSS test (Laakso, Brunnegård, Hartelius, & Ahlsén, 2000) and two digit span tasks. Relationships between the demographic variables, VWM and BeSS were investigated both with bivariate correlations and multiple regression analysis. The results present the norms for BeSS. The correlations and multiple regression analysis show that demographic variables had limited influence on test performance. Measures of VWM were moderately related to total BeSS score and weakly to moderately correlated with five of the seven subtests. To conclude, education has an influence on the test as a whole but measures of VWM stood out as the most robust predictor of HLL. [ABSTRACT FROM AUTHOR]

This study explored within-subjects differences in the performance of 40 bilingual participants on the English and Spanish versions of the Wechsler Adult Intelligence Scale (WAIS) Digit Span task. To test the linguistic hypothesis that individuals would perform worse in Spanish because of its syllabic demand, we compared the number of syllables correctly recalled by each participant for every correct trial. Our analysis of the correct number of syllables remembered per trial showed that participants performed significantly better (i.e., recalling more syllables) in Spanish than in English on the total score. Findings suggest the Spanish version of the Digit Span (total score) was significantly more difficult than the English version utilizing traditional scoring methods. Moreover, the Forward Trial, rather than the Backward Trial, was more likely to show group differences between both language versions. Additionally, the Spanish trials of the Digit Span were correlated with language comprehension and verbal episodic memory measures, whereas the English trials of the Digit Span were correlated with confrontational naming and verbal fluency tasks. The results suggest that more research is necessary to further investigate other cognitive factors, rather than just syllabic demand, that might contribute to performance and outcome differences on the WAIS Digit Span in Spanish-English bilinguals. [ABSTRACT FROM AUTHOR]

In the widely used Corsi Block Test and Wechsler Spatial Span Tests, participants must reproduce sequences of blocks in the order touched by the examiner until two trials are missed at the same sequence length. The examiner records either the maximum number of blocks correctly reported or the total number of correct lists. Here, we describe a computerized spatial span test (C-SST) that uses psychophysical procedures to quantify visuospatial mean span (MnS) with sub-digit precision. Results from 187 participants ranging in age from 18 to 82 years showed that accuracy declined gradually with list length around the MnS (by ∼30% per item). Simulation studies revealed high variance and biases in CBT and Wechsler measures, and demonstrated that the C-SST provided the most accurate estimate of true span (i.e., the sequence length producing 50% correct). MnS declined more rapidly with age than mean digit span (MnDS) measured in the same participants. Response times correlated with both MnS and MnDS scores. Error analysis showed that omission and transposition errors predominated, with weaker primacy and recency effects in spatial span than digit span testing. The C-SST improves the precision of spatial span testing and reveals significant differences between visuospatial and verbal working memory. [ABSTRACT FROM AUTHOR]

This study examined performance in the forward and backward digit span task of the Wechsler Intelligence Scale for Children–Fourth Edition (WISC–IV) in a large group of children with specific learning disorder (SLD) as compared with a group of typically developing children matched for age and sex. Our results further support the hypothesis that the intellectual difficulties of children with SLD involve working memory in the forward digit span task to a greater extent than in the backward digit span task. The correlation of the two spans with a General Ability Index (GAI) was similar in SLD, and smaller in magnitude than in typically developing children. Despite a GAI within normal range, children with SLD had difficulty with both digit span tasks, but more so for forward span. This pattern was similar for different SLD profiles with clinical diagnoses of dyslexia and mixed disorder, but the impairments were more severe in the latter. Age differences were also investigated, demonstrating larger span impairment in older children with SLD than in younger. [ABSTRACT FROM PUBLISHER]

The purpose of this study was to examine verbal fluency and verbal short-term memory in 12 adults with Down syndrome (DS) and 12 adults with Intellectual Disability (ID) of unspecified origin, matched for receptive vocabulary and chronological age. Participants’ performance was assessed on two conditions of a verbal fluency test, namely, semantic and phonemic fluency. In addition to the total number of correct words produced, the use of clustering and switching strategies was also evaluated. In order to investigate the likely relations of verbal short-term memory with the test variables, a digit span task was administered. According to the results of the study, the two groups differed significantly on the average phonemic cluster size, with the ID group outperforming the DS group. Regarding the within-group comparisons, a relatively similar pattern of results was found for the two groups, indicating higher scores on all the measures involved in the semantic test than the phonemic one. The examination of the relation of verbal short-term memory with the verbal fluency test measures revealed that, in the DS group, only the total words produced in the semantic and the phonemic test and the number of phonemic switches were significantly associated with verbal short-term memory. Additionally, in both groups, word productivity in the semantic and the phonemic test was positively associated with the number of switches. The observed similarities and differences in the performance of the two groups, as well as the associations that emerged among the test variables in each group, are discussed. [ABSTRACT FROM PUBLISHER]

The Wechsler Adult Intelligence Scale (WAIS) is one of the most frequently used tests among psychologists. In the fourth edition of the test (WAIS-IV), the subtests Digit Span and Letter-Number Sequencing are expanded for better measurement of working memory (WM). However, it is not clear whether the new extended tasks contribute sufficient complexity to be sensitive measures of manipulation WM, nor do we know to what degree WM capacity differs between the visual and the auditory modality because the WAIS-IV only tests the auditory modality. Performance by a mixed sample of 226 patients referred for neuropsychological examination on the Digit Span and Letter-Number Sequencing subtests from the WAIS-IV and on Spatial Span from the Wechsler Memory Scale-Third Edition was analyzed in two confirmatory factor analyses to investigate whether a unitary WM model or divisions based on modality or level/complexity best fit the data. The modality model showed the best fit when analyzing summed scores for each task as well as scores for the longest span. The clinician is advised to apply tests with higher manipulation load and to consider testing visual span as well before drawing conclusions about impaired WM from the WAIS-IV. [ABSTRACT FROM AUTHOR]

The tablet computer initiates an important step toward computerized administration of neuropsychological tests. Because of its lack of standardization, the Corsi Block-Tapping Task could benefit from advantages inherent to computerization. This task, which requires reproduction of a sequence of movements by tapping blocks as demonstrated by an examiner, is widely used as a representative of visuospatial attention and working memory. The aim was to validate a computerized version of the Corsi Task (e-Corsi) by comparing recall accuracy to that on the standard task. Forty university students (Mage = 22.9 years,SD = 2.7 years; 20 female) performed the standard Corsi Task and the e-Corsi on an iPad 3. Results showed higher accuracy in forward reproduction on the standard Corsi compared with the e-Corsi, whereas backward performance was comparable. These divergent performance patterns on the 2 versions (small-to-medium effect sizes) are explained as a result of motor priming and interference effects. This finding implies that computerization has serious consequences for the cognitive concepts that the Corsi Task is assumed to assess. Hence, whereas the e-Corsi was shown to be useful with respect to administration and registration, these findings also stress the need for reconsideration of the underlying theoretical concepts of this task. [ABSTRACT FROM PUBLISHER]

Introduction:N-back tasks are commonly used in functional neuroimaging studies to identify the neural mechanisms supporting working memory (WM). Despite widespread use, the clinical utility of these tasks is not well specified. This study compared N-back performance during functional magnetic resonance imaging (fMRI) with task data acquired outside of the scanner as a measure of reliability across environment. N-back task validity was examined in relation to performance and rater-based measures used clinically to assess working memory.Method:Forty-three healthy adults completed verbal and object N-back tasks during fMRI scanning and outside the scanner. Task difficulty was varied parametrically (0, 1, and 2-back conditions). Order of N-back task completion was stratified by modality (verbal/object) and environment. Participants completed the Digit Span (DS) and provided self-ratings using the Behavior Rating Inventory of Executive Function (BRIEF-WM).Results:Mean verbal and object N-back accuracy was above 95% across load conditions; task difficulty was effectively manipulated across load conditions. Performance accuracy did not significantly differ by environment. N-back reaction time was slower during fMRI (F= 6.52,p= .01, ηp2= .13); participants were faster when initially completing tasks outside the scanner (ηp2= .10–.15). Verbal 2-back accuracy was significantly related to DS performance (r= .36,p= .02). N-back performance was not related to BRIEF-WM.Conclusions:Our results provide evidence for reliability of N-back accuracy during fMRI scanning; however, reliability of reaction time data is affected by order of task presentation. Data regarding construct validity are inconsistent and emphasize the need to consider clinical utility of behavioral measures in the design and interpretation of functional neuroimaging studies. [ABSTRACT FROM PUBLISHER]

A 42-year-old man suffered damage to the left supra-sylvian areas due to a stroke and presented with verbal short-term memory (STM) deficits. He occasionally could not recall even a single syllable that he had heard one second before. A study of mismatch negativity using magnetoencephalography suggested that the duration of auditory sensory (echoic) memory traces was reduced on the affected side of the brain. His maximum digit span was four with auditory presentation (equivalent to the 1st percentile for normal subjects), whereas it was up to six with visual presentation (almost within the normal range). He simply showed partial recall in the digit span task, and there was no self correction or incorrect reproduction. From these findings, reduced echoic memory was thought to have affected his verbal short-term retention. Thus, the impairment of verbal short-term memory observed in this patient was "pure auditory" unlike previously reported patients with deficits of the phonological short-term store (STS), which is the next higher-order memory system. We report this case to present physiological and behavioral data suggesting impaired short-term storage of verbal information, and to demonstrate the influence of deterioration of echoic memory on verbal STM. [ABSTRACT FROM AUTHOR]

Background: Seasonal variations in mood and behavior are common among the general population and may have a deteriorating effect on cognitive functions. Aims: In this study the effect of seasonal affective disorder (SAD-like symptoms) on cognitive test performance were evaluated in more detail. Methods: The data were derived from the study Mental Health in Early Adulthood in Finland. Participants ( n = 481) filled in a modified Seasonal Pattern Assessment Questionnaire (SPAQ) and performed cognitive tests in verbal and visual skills, attention and general intelligence. Results: SAD-like symptoms, especially regarding the seasonal variations in weight and appetite, had a significant effect on working memory (Digit Span Backward, P = 0.008) and auditory attention and short-term memory (Digit Span Forward, P = 0.004). The seasonal variations in sleep duration and mood had an effect on auditory attention and short-term memory (Digit Span Forward, P = 0.02 and P = 0.0002, respectively). The seasonal variations in social activity and energy level had no effect. Conclusions: Seasonal changes in mood, appetite and weight have an impairing effect on auditory attention and processing speed. If performance tests are not to repeated in different seasons, attention needs to be given to the most appropriate season in which to test. [ABSTRACT FROM AUTHOR]

We analyzed error patterns during digit span (DS) testing in four experiments. In Experiment 1, error patterns analyzed from a community sample of 427 subjects revealed strong primacy and recency effects. Subjects with shorter DSs showed an increased incidence of transposition errors in comparison with other error types and a greater incidence of multiple errors on incorrect trials. Experiment 2 investigated 46 young subjects in three test sessions. The results replicated those of Experiment 1 and demonstrated that error patterns of individual subjects were consistent across repeated test administrations. Experiment 3 investigated 40 subjects from Experiment 2 who feigned symptoms of traumatic brain injury (TBI) with 80% of malingering subjects producing digit spans in the abnormal range. A digit span malingering index (DSMI) was developed to detect atypical error patterns in malingering subjects. Overall, 59% of malingering subjects with abnormal digit spans showed DSMIs in the abnormal range and DSMI values correlated significantly with the magnitude of malingering. Experiment 4 compared 29 patients with TBI with a new group of 38 control subjects. The TBI group showed significant reductions in digit span. Overall, 32% of the TBI patients showed DS abnormalities and 11% showed abnormal DSMIs. Computerized error-pattern analysis improves the sensitivity of DS assessment and can assist in the detection of malingering. [ABSTRACT FROM AUTHOR]

Subjective memory complaint (SMC) is common among elderly people, and is thought to be part of mild cognitive impairment (MCI). We evaluated whether impaired digit span (IDS) in older people with SMC can predict wider impairment in future neuropsychological tests that correspond to MCI. After a mean of 6.6 years from the initial assessment, we reevaluated 16 subjects with SMC and normal digit span (NDS) scores (mean age 57.6 ± 8.1 years) and 28 subjects with SMC and IDS scores (mean age 59.7 ± 9.9 years). The IDS group showed wider cognitive decline in tests of short-term verbal memory and category verbal fluency compared to the NDS group. IDS scores indicate an earlier step for conversion of SMC to MCI. [ABSTRACT FROM AUTHOR]

Twenty-four studies utilizing the Wechsler Adult Intelligence Scale (WAIS) Digit Span subtest-either the Reliable Digit Span (RDS) or Age-Corrected Scaled Score (DS-ACSS) variant-for malingering detection were meta-analytically reviewed to evaluate their effectiveness in detecting malingered neurocognitive dysfunction. RDS and DS-ACSS effectively discriminated between honest responders and dissimulators, with average weighted effect sizes of 1.34 and 1.08, respectively. No significant differences were found between RDS and DS-ACSS. Similarly, no differences were found between the Digit Span subtest from the WAIS or Wechsler Memory Scale (WMS). Strong specificity and moderate sensitivity were observed, and optimal cutting scores are recommended. [ABSTRACT FROM AUTHOR]

We measured digit span (DS) in two experiments that used computerized presentation of randomized auditory digits with performance-adapted list length adjustment. A new mean span (MS) metric of DS was developed that showed reduced variance, improved test-retest reliability, and higher correlations with the results of other neuropsychological test results when compared to traditional DS measures. The MS metric also enhanced the sensitivity of forward versus backward span comparisons, enabled the development of normative performance criteria with subdigit precision, and elucidated changes in DS performance with age and education level. Computerized stimulus delivery and improved scoring metrics significantly enhance the precision of DS assessments of short-term verbal memory. [ABSTRACT FROM AUTHOR]

Research has shown that verbal short-term memory span is shorter in individuals with Down syndrome than in typically developing individuals of equivalent mental age, but little attention has been given to variations within or across groups. Differences in the environment and in particular educational experiences may play a part in the relative ease or difficulty with which children remember verbal material. This article explores the performance of 26 Egyptian pupils with Down syndrome and 26 Egyptian typically developing children on two verbal short-term memory tests: digit recall and non-word repetition tasks. The findings of the study revealed that typically developing children showed superior performance on these tasks to that of pupils with Down syndrome, whose performance was both lower and revealed a narrower range of attainment. Comparisons with the performance of children with Down syndrome in this study suggested that not only did the children with Down syndrome perform more poorly than the typically developing children, their profile also appeared worse than the results of studies of children with a similar mental age with Down syndrome carried out in western countries. The results from this study suggested that, while deficits in verbal short-term memory in Down syndrome may well be universal, it is important to recognise that performances may vary as a consequence of culture and educational experiences. The significance of these findings is explored with reference to approaches to education and how these are conceptualised in relation to children with disabilities. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare the coordinative function of the central executive of working memory in matched groups of controls and persons with traumatic brain injury (TBI) with long-term impairments in functioning, using a dual-task paradigm. The dual-task procedure required participants to complete digit span and tracing tasks separately and then together to produce a change index that reflects loss of productivity on the dual trial. A TBI group and a matched group of controls were compared on this task and on ratings of social competency and neuropsychological tests. The two groups were found to differ in social competence, in the number of dysexecutive symptoms, and on dual-task performance, but not on any other measures of cognitive ability. Poor performance on the dual task was found only in persons with initial very severe TBI. There was no evidence that the group difference on the dual task was the consequence of increased task difficulty level, distribution of attention, or other within-task biases. Performance on the dual task was correlated with dysexecutive symptoms and social competency (in particular interpersonal and cognitive competence), but not with other tests of executive functioning. The findings suggest that deficits in the coordinative function persist in long-term survivors of TBI after other deficits in executive functioning may have resolved and are associated with lower ratings of current interpersonal competence. [ABSTRACT FROM AUTHOR]

Previous research suggests that stress can influence a broad range of memory functions. In this study we investigated the effect of a naturalistic stressor, examination stress, on working memory in young adults. In order to accomplish this aim, participants were tested on psychological and hormonal measures of stress and on Digit Span, once during a low stress period and once during a high stress period. The high examination stress condition was associated with an increase in cortisol and subjective impressions of stress. Although Digits Forward performance did not vary with examination stress, Digits Backward performance improved. These findings suggest that mild increases in stress are associated with improvement in the manipulation component of working memory. However, no correlations were found between working memory and either cortisol or psychological stress. Thus the mechanism by which mild naturalistic stressors improve the manipulation component of working memory needs further investigation. [ABSTRACT FROM AUTHOR]

Single case: DT is a savant with exceptional abilities in numerical memory and mathematical calculations. DT also has an elaborate form of synaesthesia for visually presented digits. Further more, DT also has Asperger syndrome (AS). We carried out two preliminary investigations to establish whether these conditions may contribute to his savant abilities. Neuroimaging: In an fMRI digit span study, DT showed hyperactivity in lateral prefrontal cortex when encoding digits, compared with controls. In addition, while controls showed raised lateral prefrontal activation in response to structured (compared to unstructured) sequences of digits, DT's neural activity did not differ between these two conditions. In addition, controls showed a significant performance advantage for structured, compared with unstructured sequences whereas no such pattern was found for DT. We suggest that this performance pattern reflects that DT focuses less on external mathematical structure, since for him all digit sequences have internal structure linked to his synaesthesia. Finally, DT did not activate extra-striate regions normally associated with synaesthesia, suggesting that he has an unusual and more abstract and conceptual form of synaesthesia. This appears to generate structured, highly-chunked content that enhances encoding of digits and aids both recall and calculation. Neuropsychology: People with AS preferentially attend to local features of stimuli. To test this in DT, we administered the Navon task. Relative to controls, DT was faster at finding a target at the local level, and was less distracted by interference from the global level. Discussion: The propensity to focus on local detail, in concert with a form of synaesthesia that provides structure to all digits, may account for DT's exceptional numerical memory and calculation ability. This neural and cognitive pattern needs to be tested in a series of similar cases, and with more constrained control groups, to confirm the significance of this association. [ABSTRACT FROM AUTHOR]

This study assessed the effects of stimulus misidentification and memory processing errors on immediate memory span in 25 normal-hearing adults exposed to degraded auditory input simulating signals provided by a cochlear implant. The identification accuracy of degraded digits in isolation was measured before digit span testing. Forward and backward digit spans were shorter when digits were degraded than when they were normal. Participants’ normal digit spans and their accuracy in identifying isolated digits were used to predict digit spans in the degraded speech condition. The observed digit spans in degraded conditions did not differ significantly from predicted digit spans. This suggests that the decrease in memory span is related primarily to misidentification of digits rather than memory processing errors related to cognitive load. These findings provide complementary information to earlier research on auditory memory span of listeners exposed to degraded speech either experimentally or as a consequence of a hearing-impairment. [ABSTRACT FROM AUTHOR]